High frequency electric discharge device



July 1, 1958 c. E. HORTON ETAL HIGH FREQUENCY ELECTRIC DISCHARGE DEVICE7 Filed March 27, 1953 Fig. 3.

Inventors: "C|iFFord E.I-Ior-ton Hsiung Hsu, M

- Their Attorney.

Zilllfldd Patented July 1, 1958 HIGH FREQUENCY ELECTRIC DISCHARGE DEVICECliiiord E. Horton and Hsiung Hen, Owensboro, Ky., as signors to GeneralElectric Company, a corporation of New York Application March 2'7, 1953,Serial No. 344,957 9 Claims. (Cl. 313-24tl) facture which characterizesmore conventional receiving type tubes. Previous attempts to providetubes for satisfactory operation in this range have involved structureswhich are rather expensive to manufacture. The disk seal or lighthousetube is one well-known prior art type of device capable of operating inthis high frequency range but as is readily appreciated by those skilledin the art these tubes, involving large sealing areas, are ratherexpensive to manufacture and are not well suited for mass production ata price which is attractive for such applications as televisionreceivers.

The present invention has for an important object the provision of ahigh frequency tube design particularly suited for grounded gridoperation and lending itself to usual mass production techniquesemployed for receiving type tubes.

It is a further object of the invention to provide a high frequencyelectric discharge device of single ended construction.

It is a still further object of the invention to provide an improvedhigh frequency electric discharge device in which the grid inductancecommon to the input and output circuits is minimized.

It is still another object of the invention to provide a simplifiedstructure for a high frequency electric discharge device which ischaracterized in its operation by a minimum variation of input impedancewith frequency due to feed through resulting from coupling between theinput and output circuits.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds, reference being had tothe accompanying drawing and its scope will be pointed out in theappended claims. In the drawing,

Figure l is a perspective view partially broken away showing an electricdischarge device embodying our invention:

Figure 2 is an enlarged perspective view of a part of the device shownin Figure 1 with the parts partially broken away and with the length ofthe lead-in conductors exaggerated to show their location in relation tothe electrodes to which they are connected; and

Figure 3 is a flux plot showing the degree of inductive isolationbetween the input and output circuits of the device. 7

Referring now to the drawing, the present invention has been shownembodied in a triode device particularly suited for use as a groundedgrid amplifier at frequencies up to 900 megacycles. The device asillustrated comprises a standard miniature tube envelope 1 including astem or header 2 through which the nine pins or lead-in conductors,designated by numerals 3-11, inclusive, are sealed in a circular array.

The electrode assembly or mount includes an indirectly heated cathode12, a grid 13 including a pair of spaced side rods 14 and 15 and anoverwound wire l6 and a box like anode 17. As illustrated, the cathodesleeve 12 is rectangular in cross section and is heated by a filamentaryheater element having terminals 13 and 19 connected with lead-inconductors i and 5. Unlike most receiving type tubes, the mountstructure in accord ance with one feature of the present invention ismounted with the axis thereof horizontal, that is transverse withrespect to the axis of the envelope 1 and the flattened grid is mountedin a generally horizontal plane. In accordance with the usual practice,the electrodes are supported in mutually insulated relation by means ofa pair of insulating spacer members 249 and 21 (shown only in Fig. 1).

One of the requirements for high frequency operation of a grounded gridtube is that the grid and associated structure provide a ratherefiective shield between the anode and cathode. In accordance with thepresent invention this is accomplished by specially designed con ductingor shield members which are secured to the grid side rods 14 and 15 atopposite ends of the mount and on the exterior of the spacers 2d and 21.As illustrated, conducting members or shields 22 and 23 include a flatportion 24 which is bonded to the extending ends of the grid side rodsand form essentially extensions of the grid plane. From these portions24 the shields each include a depending portion 25 which extends atright angles thereto and then extends inwardly toward the spacers 20 and21.

While the arrangement of the shields just described is a very importantconsideration with respect to the shielding between the cathode andanode and the resulting reduction in the capacitive coupling betweenthese electrodes, the arrangement of the lead-in conductors with respectto the various electrodes and particularly with respect to the shieldmembers forms an important part of the present invention andparticularly contributes to the effective inductive isolation of theinput and output circuits, that is, the circuit between the grid andcathode on the one hand and the grid and anode on the other. From Figs.1, 2, and 3, it will be apparent that the lead-in conductors areconnected to the various electrodes in the following order: Conductors 3and 6 are connected to opposite edges of the shield member 22 connectedto the grid at one end; lead-in conductors 4- and 5 are connected to theheater leads; lead-in conductor 7 is connected directly to the anodebetween the insulating spacers and also between the shield members 22and and lead-in conductors 8 and iii are connected to opposite edges ofthe shield member 23 at the opposite end of the mount, with conductor 9connected to tie shield member near the middle thereof in rather closeprerimity to the lead-in conductor iti which is connected with thecathode sleeve.

The multiple grid connections described above tend to minimize the totalinductance in the grid circuit connections. More important, however, tothe successful operation of this tube at high frequencies is therelatively complete inductive isolation of the input and output circuitsresulting from the location of the lead-in. conductors relative to eachother and to the associated electrodes. It will be noted from aconsideration of Fig. 3 that the fields associated with the grid-platecircuit (conductor 7 and edges of shields connected to lead-ins 6 and 3)are essentially isolated from the fields associated with thegrid-cathode circuit (conductor 10 and central portion of shieldconnected with lead-in 9). In effect, diiferent portions of the gridshields and diiterent grid lead-in conductors are involved in thegrid-plate circuit from the 3 grid lead-ins and portions of the gridshield involved in the grid-cathode circuit.

This construction has been found to provide a very marked improvement inthe highfrequency characteristics of the device and, as will be apparentto those srilled in the art, is accomplished without any substantialcomplication of the structure froma general manufacturing and assemblystandpoint. The tube still remains, as far as the basic manufacturingsteps are involved, a single ended receiving type tube involving a stem,an envelope, and an eiectrode mount.

While we have described and claimed the particular embodiment of ourinvention, it will be apparent to those skilled in the art, that changesand modifications may be made without departing from our invention inits broader aspects, and we aim therefore in the appended claims tocover all such changes and modifications as fall Within the true spiritand scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited tates is:

l. A high frequency electric discharge device for grounded gridoperation including a generally cylindrical envelope including a closureat one end having a plurality of lead-in conductors sealed therethroughin a ircuiar array, an electrode mount including a cathode, a grid, ananode supported in mutually insulated and concentric relation in theorder named with the anode the outermost electrode, means supportingsaid electrode mount in said envelope with the axis extending generallytransverse to the axis of said envelope, a shield member extendingoutwardly from each end of said grid and downwardly toward said closure,lead-in conductors connected to each of said shields near opposite edgesthereof and providing grid circuit connections, a lead-in conductorconnected with said anode between said shields and extending throughsaid closure member between lead-in conductors connected with differentones of said shields, and a cathode connection with a lead-in conductorpsi tioned between the lead-in conductors connected with one of saidshields to limit the inductive coupling between said grid-anode circuiton the one hand and the grid cathode-circuit on the other.

2. An electric discharge device including an elongated envelopeincluding a closure at one end having a plurality of lead-in conductorssealed therethrough, an anode, a control grid, and a cathode supportedin insulated relation within said envelope and extending generallytransverse to the axis of said envelope, shield members of conductingmaterial connected with and forming an extension of each end of saidcontrol grid and each'in-' eluding a portion extending toward saidclosure, one of said lead-in conductors being connected with said anodebetween said portions, another of said lead-in conductors beingconnected with said cathode and located on the opposite side of one ofsaid portions and a lead-in conductor connected with each of saidportions.

3. An electric discharge device including an elongated envelopeincluding a closure at one end having a plurality of leaddn conductorssealed therethrough, an anode, a control grid, and a cathode supportedin insulated relation within said envelope and extending generallytransverse to axis of said envelope, a shield member of conductingmaterial connected with an forming an extension of said control grid andincluding a portion extending toward said closure, one of said lead-inconductors being connected with said anode on one side of said portion,another of said lead-in conductors being connected with said cathode andlocated on the opposite side of said portion and at least two lead-inconductors connected with said portion.

A high frequency electric discharge device for grounded grid operationincluding an anode, a cathode, and acontrol grid interposedtherebetween, a conducting member of extended area connected to providesmooth electrical continuity with said control grid, a lead-incon- 4ductor connected with said anode and lying on one side of saidconducting member, a lead-in conductor connected with said cathode andlocated on the opposite side of said conducting member, and first andsecond lead-in conductors connected with said conducting member, saidfirst l ad-in conductor being closer to the 1ead-in conductor connectedwith the anode and the second lead-in conductor being closer to thelead-in conductor connected with the cathode.

5. A high frequency electric discharge device for grounded gridoperation including an anode, a cathode, and a control grid interposedtherebeween, conducting members extending from each end of said gidmember and a plurality of lead-in conductors connected with saidelectrodes including at least two conductors connected with each of saidconducting members, a lead-in conductor connected with said anode and lcated between the connectors connected with one said conducting membersand the conductors connected with the other of said conducting members,and a lead-in conductor con nected with said cathode and located betweenthe lead-in conductors connected with one of said conducting memhers.

6. A high frequency eiectric discharge device grounded grid operationincluding a cylindr "ivciops, an elcctrodemount including an anode, acathode, and a control grid interposed therebetween, said mountextending transversely to the axis of said envelope, conducting membersextending from each end of s d grid member and toward the end of saidenvelope, a plurality of lead-in conductors extending through said endof said envelope and connected with said electrodes including at leasttwo conductors connected with each of said conducting members, a lead-inconductor connected with said anode and located between the conductorsconnected with one of said conducting members and the conductorsconnected with the other of said conducting members, and a lead-inconductor connected with said cathode and located between the lead-inconductors connected withone of said conducting members.

7. An electric discharge device including an envelope including aclosure at one end having a plurality of lead-in conductors sealedtherethrough, an anode, a grid and a. cathode supported in insulatedrelation within said envelope, a conducting member connected to at leasttwo spaced points of said grid and forming an extension thereof, saidmember having a first portion substantially coplanar with said grid anda second portion extending to Ward said closure, one of said lead-inconductors being connected with said anode on one side of saidsmo'ndportion, another of said lead-in conductors being connected with saidcathode and located on the opposite side of said second portion.

8. A high frequency electric discharge device comprising an anode, acathode and an elongated grid ii crposed therebetween, electric shieldmeans connected at re on 0* site ends of said grid to provide smoothelectrical continuity therewith, and a plurality of conductiveconnections to said shield means and arranged in parailel whereby thenet inductance thereof is minimized.

9. A high frequency electric discharge device comprising anlanode, acathode, and an elongated grid interposed therebetween, electric shieldmeans connected to at least two longitudinally spaced points on d grid,and a plurality of lead-in conductive connect is to said shield means.

References Cited in the tile of this patent UNITED STATES PATENTS

